Evidence from cardiovascular research has indicated that the nervous system plays a major functional role in the control of cardiovascular dynamics. Specific investigations have shown that central nervous system structures are intimately involved in cardiovascular regulation and that many of these regulatory structures are of primary importance in the regulation of behavioral patterns that are associated with psychological stressors. In addition, controlled behavioral stressors have been shown to be strongly physiologically linked to potentially harmful cardiovascular events. In recent years, particular emphasis has been placed on the potential role of behavioral stressors in cardiovascular diseases such as hypertension. These previous investigations clearly point to an interactive point of convergence among behavioral stress, central nervous system and cardiovascular dynamics. The objective of the proposed research is to begin an investigation of this point of convergence by studying the relationship between central nervous system neurochemistry and cardiovascular dynamics in conscious dogs during controlled behavioral stress. It is believed that through this strategy, it will be possible to gain a better understanding of the neural and behavioral mechanisms that may play a role in the precipitation of cardiovascular pathologies such as hypertension.